1. Field of the Invention
The present invention relates to a hydraulic excavator.
2. Background Information
An exhaust processing apparatus is mounted to a hydraulic excavator. The exhaust processing apparatus is connected to an engine through a connecting pipe in order to process exhaust from the engine. The exhaust processing apparatus includes a selective catalytic reduction apparatus. The selective catalytic reduction apparatus reduces nitrogen oxide (NOx) in exhaust.
The selective catalytic reduction apparatus processes the exhaust using a reducing agent such as aqueous urea. As a result, it is necessary to arrange a reducing agent tank which retains the reducing agent in the hydraulic excavator. However, there is a possibility that the reducing agent may change form in a high-temperature environment. Therefore, in Japan Patent Laid-open Patent Publication No. 2010-261373, the reducing agent tank is arranged to be dispersed into a plurality of locations in the hydraulic excavator. Then, it is disclosed that, in a high-temperature environment, a change in form of the reducing agent is suppressed by the reducing agent tank being arranged at locations which are separated from sources of heat.
In Japan Patent Laid-open Patent Publication No. 2010-261373, the arrangement of the reducing agent tank is considered but the arrangement of a reducing agent pipe for supplying the reducing agent to the selective catalytic reduction apparatus is not considered at all. However, there is a possibility that the reducing agent which flows in the reducing agent pipe may be change form due to high temperatures in a case where the reducing agent pipe is placed in a high-temperature environment, even when the reducing agent tank is arranged to avoid the high-temperature environment. In particular, the reducing agent may be supplied at an extremely slow speed such as several centimeters per second. In this case, the reducing agent which flows in the reducing agent pipe is significantly affected by heat due to the temperature of the environment in the surroundings of the reducing agent pipe.
In addition, when the reducing agent tank is arranged at a position which is away from an engine compartment in order to avoid the high-temperature environment, the length of the reducing agent pipe is lengthened. When the length of the reducing agent pipe is lengthened, the effects of heat due to the temperature of the environment in the surroundings of the reducing agent pipe tend to increase. In addition, when the length of the reducing agent pipe is lengthened, it is difficult to arrange the reducing agent pipe without interfering with other members. When the reducing agent pipe interferes with the other members, there is a possibility that the reducing agent pipe may be damaged. Alternatively, there may also be a possibility that the reducing agent pipe will be damaged due to external factors.
An object of the present invention is to provide a hydraulic excavator where it is possible to reduce the effects of heat on the reducing agent and where it is possible to protect the reducing agent pipe.
A hydraulic excavator according to a first aspect of the present invention is provided with an engine, a revolving frame, an engine compartment, an exhaust processing unit, a reducing agent injection apparatus, a reducing agent tank, a reducing agent supply pump, and a reducing agent pipe. The revolving frame supports the engine. The engine compartment accommodates the engine. The exhaust processing unit includes a selective catalytic reduction apparatus which processes exhaust from the engine. The exhaust processing unit is arranged inside the engine compartment. The reducing agent injection apparatus is attached to the exhaust processing unit. The reducing agent injection apparatus injects a reducing agent which is supplied to the selective catalytic reduction apparatus. The reducing agent tank is arranged outside the engine compartment. The reducing agent tank retains the reducing agent. The reducing agent supply pump is arranged outside the engine compartment. The reducing agent supply pump supplies the reducing agent from the reducing agent tank to the reducing agent injection apparatus. The reducing agent pipe connects the reducing agent supply pump and the reducing agent injection apparatus. The revolving frame includes a pipe frame. The reducing agent pipe is arranged from the reducing agent supply pump to the reducing agent injection apparatus so as to pass through an inner space of the pipe frame.
A hydraulic excavator according to a second aspect of the present invention is the hydraulic excavator of the first aspect where a vehicle body frame is further provided. The vehicle body frame is disposed on the revolving frame and includes a plurality of column members. The exhaust processing unit is supported by the vehicle body frame. The reducing agent pipe is arranged so as to pass through the inner space of the pipe frame and inner space of the column member of the vehicle body frame.
A hydraulic excavator according to a third aspect of the present invention is the hydraulic excavator of the second aspect where the plurality of column members includes a first column member. The first column member extends upward from the revolving frame toward the exhaust processing unit. The reducing agent pipe is arranged so as to pass through the inner space of the pipe frame and an inner space of the first column member.
A hydraulic excavator according to a fourth aspect of the present invention is the hydraulic excavator of the second aspect where the plurality of column members includes a second column member. The second column member is arranged outside of the exhaust processing unit in the vehicle width direction. The reducing agent pipe is arranged so as to pass through the inner space of the pipe frame and an inner space of the second column member.
A hydraulic excavator according to a fifth aspect of the present invention is the hydraulic excavator of the fourth aspect where an outer cover is further provided. The outer cover is attached to the second column member.
A hydraulic excavator according to a sixth aspect of the present invention is the hydraulic excavator of any of the first to fifth aspects where the revolving frame includes a center frame. The center frame is arranged below the engine. The pipe frame is arranged outside of the center frame in the vehicle width direction.
A hydraulic excavator according to a seventh aspect of the present invention is the hydraulic excavator of any of the first to fifth aspects where the pipe frame is arranged furthest to the outside of the revolving frame in the vehicle width direction.
A hydraulic excavator according to an eighth aspect of the present invention is the hydraulic excavator of any of the first to fifth aspects where the pipe frame extends in the vehicle front and back direction.
A hydraulic excavator according to a ninth aspect of the present invention is the hydraulic excavator of any of the first to fifth aspects, where a fuel tank which retains fuel is further provided. The fuel tank is arranged between the reducing agent supply pump and the engine compartment.
A hydraulic excavator according to a tenth aspect of the present invention is the hydraulic excavator of any of the first to fifth aspects where a hydraulic fluid tank which retains hydraulic fluid is further provided. The hydraulic fluid tank is arranged between the reducing agent supply pump and the engine compartment.
A hydraulic excavator according to an eleventh aspect of the present invention is the hydraulic excavator of any of the second to fifth aspects where a counterweight is further provided. The counterweight is arranged to be adjacent to the engine compartment. The column member through which the reducing agent pipe passes covers at least the counterweight side of the reducing agent pipe.
A hydraulic excavator according to a twelfth aspect of the present invention is the hydraulic excavator of any of the second to fifth aspects where the exhaust processing unit further includes a diesel particulate filter apparatus and a connecting pipe. The diesel particulate filter apparatus processes exhaust from the engine. The connecting pipe connects the selective catalytic reduction apparatus with the diesel particulate filter apparatus. The reducing agent injection apparatus is attached to the connecting pipe. The reducing agent injection apparatus injects the reducing agent into the connecting pipe.
In the hydraulic excavator according to the first aspect of the present invention, the reducing agent tank and the reducing agent supply pump are arranged outside the engine compartment. As a result, it is possible to reduce the effects of heat from the engine compartment with regard to the reducing agent in the reducing agent tank and the reducing agent in the reducing agent supply pump. In addition, the reducing agent pipe is arranged from the reducing agent supply pump to the reducing agent injection apparatus so as to pass through an inner space of the pipe frame. As a result, it is possible to reduce the effects of heat on the reducing agent in the reducing agent pipe even when the reducing agent pipe is lengthened. In addition, since the reducing agent pipe is arranged so as to pass through the inner space of the pipe frame, it is possible to protect the reducing agent pipe using the pipe frame.
In the hydraulic excavator according to the second aspect of the present invention, using the inner space of the column member of the vehicle body frame which supports the exhaust processing unit, it is possible to pass the reducing agent pipe therethrough. Due to this, it is possible to further reduce the effects of heat on the reducing agent in the reducing agent pipe.
In the hydraulic excavator according to the third aspect of the present invention, it is possible to arrange the reducing agent pipe so as to extend upward from the revolving frame toward the exhaust processing unit. Accordingly, it is possible to arrange the reducing agent pipe such that the length of the reducing agent pipe path is as short as possible.
In the hydraulic excavator according to the fourth aspect of the present invention, it is possible to arrange the reducing agent pipe so as to pass through a position which is close to the outside of the vehicle. Due to this, it is possible to further reduce the effects of heat on the reducing agent in the reducing agent pipe.
In the hydraulic excavator according to the fifth aspect of the present invention, it is possible to arrange the reducing agent pipe so as to pass through a position which is close to the outside of the vehicle. Due to this, it is possible to further reduce the effects of heat on the reducing agent in the reducing agent pipe.
In the hydraulic excavator according to the sixth aspect of the present invention, it is possible to arrange the reducing agent pipe so as to pass through a position which is close to the outside of the vehicle. Due to this, it is possible to further reduce the effects of heat on the reducing agent in the reducing agent pipe.
In the hydraulic excavator according to the seventh aspect of the present invention, it is possible to arrange the reducing agent pipe so as to pass through a position which is close to the outside of the vehicle. Due to this, it is possible to further reduce the effects of heat on the reducing agent in the reducing agent pipe.
In the hydraulic excavator according to the eighth aspect of the present invention, the pipe frame extends in the vehicle front and back direction. Accordingly, since it is possible to extend the reducing agent pipe to be longer in the vehicle front and back direction, it is possible to arrange the reducing agent supply pump to be considerably separated from the engine compartment.
In the hydraulic excavator according to the ninth aspect of the present invention, the fuel tank is arranged between the reducing agent supply pump and the engine compartment. Accordingly, it is possible to arrange the reducing agent supply pump to be considerably separated from the engine compartment. Due to this, it is possible to reduce the effects of heat from the engine compartment with regard to the reducing agent in the reducing agent supply pump.
In the hydraulic excavator according to the tenth aspect of the present invention, the hydraulic fluid tank is arranged between the reducing agent supply pump and the engine compartment. Accordingly, it is possible to arrange the reducing agent supply pump to be considerably separated from the engine compartment. Due to this, it is possible to reduce the effects of heat from the engine compartment with regard to the reducing agent in the reducing agent supply pump.
In the hydraulic excavator according to the eleventh aspect of the present invention, the column member through which the reducing agent pipe passes covers at least the counterweight side of the reducing agent pipe. As a result, it is possible to avoid the reducing agent pipe being exposed to the outside even in a case where the counterweight is detached from the vehicle.
In the hydraulic excavator according to the twelfth aspect of the present invention, it is possible to arrange the reducing agent pipe using the inner space of the column member so as to extend to the connecting pipe of the exhaust processing unit which is supported by the vehicle body frame.